CYSE476/ECE476 CRYPTOGRAPHY FUNDAMENTALS Project 1b: Breaking Historical Ciphers Due Date: Saturday, February 17th, 2024, 11:59pm Reading Assignment: ● C. Paar and J. Pelzl, Understanding Cryptography, Chapter 1 • W. Stallings, Cryptography and Network Security 8th edition, Chapter 3 SPRING 2024 ● A. Menezes, P. van Oorschot, and S. Vanstone, Handbook of Applied Cryptography, Chapter 7.3 • CrypTool - Online Help Help → Starting page → Functionality of CrypTool → Document encryption → Sym- metric (classic) Help → Starting page → Functionality of CrypTool → Analyzing Documents → Tools for Analysis and Symmetric Encryption (classic) 1 Installation In order to complete this lab you might want to install CrypTool on your personal computer/laptop. You can download CrypTool from https://www.cryptool.org. The recommended version of software is CrypTool 1 (CT1) ver. 1.4.42 - English. 2 Breaking the Affine Cipher Task 4 (20 points) Below please find a ciphertext obtained by encrypting a message in English using the Affine cipher. Please note that spaces and punctuation characters have been removed before encryption. The ciphertext has been divided into blocks of the size of 5 letters. BXWCG JWHWS SBWHW OJMRX GSZIB NGFFG EKHBB IKZNW JSBMZ NBXWI JNGZM JUBWH WOJMR XGSHG YWMTW JUHIZ OEMBU IKRKH HBXWB MGHGZ ZWCUI JYMZN GBQWI CSGZH ISMZO WHWSB XWCGJ WHWSS GSBXW SMQWI ZHUCG BXIKB BXWEM B Find the secret key used for encryption by breaking the Affine cipher analytically, using methods discussed in Lecture 2. Use CrypTool to analyze the frequency of letters in the ciphertext and to recover the plaintext. Your attack must be analytical and fully documented. Brute-force attacks do not count. 1 CYSE476/ECE476 CRYPTOGRAPHY FUNDAMENTALS SPRING 2024 3 Recognizing and Breaking Ciphers Task 5 (35 points + bonus points) Below please find ciphertexts of the same message encrypted using the following 6 classical ciphers available CrypTool: Caesar, Vigenere, Hill, Substitution, Playfair, and Permutation. Do your best to match ciphertexts with a cipher that could have been used to obtain the given ciphertext. Find the plaintext by breaking the Shift cipher, and then find the keys for at least 2 additional ciphers used to encrypt the now known plaintext using a known-plaintext attack. You will ob- tain extra points for any cipher broken in addition to the 3 required ones. All attacks must be documented. Brute-force attacks do not count. Please note that spaces and punctuation characters have been removed before encryption. The ciphertext has been divided into blocks of the size of 5 letters. 1. Ciphertext OEWHA DTIST BOGOH DABTE CETNW HTNEI STSWS DODNA FHUNT DLEAM SSYIM TNEHK NWNHG SACEN CSSLG SITSM FSOHR CSEAE IREIO PCIIL LGOAO YUHTO SHGHE BSNNI NONDE LEDOA EENTE DTEIN URTEY ETHGS AGEON YOROK STYOP CHOEU BWEEA EPW 2. Ciphertext QKADJ QSADJ WVQWP KJBWC AJCAQ VDNBK NNKAQ JKSLH VYNDR ARKJQ DNAPV SDKJK MEHVR GCKHA QQTBB AQSJK KJHYS CVSBK NNKAQ LHVYN DRAET SSCVS CAQKI ASDIA QRKJM TQAQT QEYSC PKWDJ BSCAI WCAPA SCAYR VJSEA QAAJQ SALCA JCVWG DJB 3. Ciphertext ONGDA OMUHA YOOVE NARXD RODRO BKHEA HWMDF OANLQ QSWIK DFDNA ACMOG NQKNA SESTS ICISM FOBFR YURBL ANNAQ VPKBQ EAHWM DFOQM IGHKD FKBPZ PKBQD RONWO QKWOC LNAEF OFBFO SZQPN DEHAU QDRWE DRGRP KGWIS BPOUO FROBL RMDRH POYCK AR 4. Ciphertext AWMQV ABMQV EIAEZ WVOEP MVPMA IQLOW LLWMA VWBXT IGLQK MKWVA QLMZI BQWVW NJTIK SPWTM AACOO MABVW WVTGB PIBOW LLWMA XTIGL QKMJC BBPIB PMAWU MBQUM AKWVN CAMAC AJGBP ZWEQV OBPMU EPMZM BPMGK IVBJM AMMVA BMXPM VPIES QVO 5. Ciphertext TCWMO GLIJB OETKJ SOUOL FBZIT OAHHC VHPSK RPHHP BMVMD SUSOG AHFFS XJCFS GPDED YZSMS KWVUY ITHFS PBDCU VSXHC VHPSK TMOQH JQWFV HLLBH ZITCE IUWEI TQGRG IKITI KFZHZ VPKAR HHZIN KZISS LLFMU EOHTI TSWRT HWTIS FLBKC MOU 6. Ciphertext JGTCC QWCMP JQRKM SQKQN YLGQV MCXTU RFLKI ZALPV VGWOV YFQCQ CXCNQ XNWYO JTQSB OQIUU NIVEJ COPYO UVOEZ XQXTU RFLKK NQSGN BQMFI RZXQX GQJGR IAERI XAUVC WZOPW WTWVT DDGMP YDGQJ EGQCA ZXJKR WDXYK ZOYLO PAZGQ RRTSB IQK 2